1. Technical Field
The present invention relates to an image forming apparatus and an image forming method according to which a light beam is irradiated upon a latent image carrier, which is driven in a sub scanning direction, in a main scanning direction which is approximately orthogonal to the sub scanning direction to thereby form a latent image.
2. Related Art
An image forming apparatus of this type comprises a photosensitive member, an exposure unit and a developer unit, and forms a latent image on the photosensitive member in the following manner. In short, a light source of the exposure unit is controlled based on image data which represents a toner image, and a deflector of the exposure unit makes a light beam from the light source scan in the main scanning direction, thereby forming a latent image corresponding to the image data on the photosensitive member. This latent image is then developed with toner and a toner image is formed.
In a light scanning apparatus of this type, a deflector makes a light beam from a light source scan on a surface to be scanned in the main scanning direction. Further, an image forming apparatus using a light scanning apparatus of this type comprises a photosensitive member and a developer unit, and the light scanning apparatus forms a toner image on the photosensitive member. That is, a light source of the light scanning apparatus is controlled based on image data which represents a toner image, thereby modulating the light beam, and as the deflector deflects the modulated light beam, a beam spot scans over the surface of the photosensitive member and a latent image corresponding to the image data is formed. This latent image is then developed with toner and a toner image is formed.
A solution proposed so far for size reduction and speed improvement of a deflector is use of a deflection mirror surface which oscillates and accordingly serves as the deflector. In other words, in this apparatus, a deflection mirror supported at a torsion bar oscillates, the light source irradiates the light beam upon the deflection mirror, and the light beam scans on the surface of the photosensitive member back and forth. JP A-2002-182147 is an example of related art.